Photographic developing process



I Patented june 27, 1939 UNITED STATES 2,163,781 rno'roommc DEVELOPING raocnss John Eggert, Leiplig, and Bruno Wendt, Dessau; Germany, assignors, by mesne assignments, to Agta Ansco Corporation, Binghamton; N; Y., a corporation of Delaware my Drawing. Application June 1, 1938, Serial No. 82,930. In Germany June I, 1935 5 Claims. (01. 95-88) Our present invention relates to photographic developers.

One of its objects is to provide a new class of developers. Further objects will be seen from the detailed specification following hereafter.-

For photographic development there have been used hitherto compounds which, apart from a few exceptions, belong to the group of aromatic polyhydric hydroxy-compounds or. of aromatic aminohydroxyand amino-compounds.

According to this invention the developer is a compound of an aliphatic or heterocyclic series containingthe atomic grouping COCHNH2- or C(OH) =qNH-.--, that is to 'say compounds which containin adjacent position a CO-group and a CHNI-Ia"=group,- or in the cnol-form an' hydroxyand an amino-group attached respectwely to two doubly-linked'carbon atoms. Any substitutents may take the place of hydrogen atoms of the amino-group', j for instance alkyl,. arylor acyl.

This new group of developers comprises both slow developers which are active only in caustic alkaline solution and also rapid'developers which act in presence of sulflte alone. A. particular advantage of the new developers is that many de-- velop under certain conditions directly in color without addition of a second component.

Aliphaticmembers of the group are, for example, diethylamino-acetone, which is a feebly active developer, aminoacetic acid ethyl ester, aminobenaoyl-acetic acid ethyl ester, and like bodies. of the heterocyclic group there may be -mentioned in particular the derivatives of 4- amlnopyrazolone-(B), the. hydrazide of orthoamin'o-phthalic acid, 3-amino-4-keto-2-iminotetrahydrothiophene and, 8 amino-4-hydroxy'-2- keto-furane-dihydride.

invenu'lhe following examples illustrate the Example! llhe following is used to develop gaslight paper in brown tints: a-amino-acetic acid ethyl-ester grams,. 6 Sodium sulflte (anhydrous) -..do 20 Sodium carbonate (anhydrous) do 10 Potassium bromide gram....' 0.5 Water r 1000 Examples" The following mixture nosed for-rapid and brilliant development of negatives:

l-phenyl--metliyl-4 amino-pyrazolone- (5) Example 3 The following developer yields, besides the silver picture an intensely yellow dyestuflf picture, which remains when the silver picture has been dissolved, for example by conversion into silver halide and fixing:

l-para-chlorophenyl-3 metn 1 4 aminopyrazolone- (5) grams- 5 Sodium sulflte (anhydrous) do 5 Potassium bromide gram 0.5

Water. cc 1000 What we claim is:

1. A processof developing an exposed silver halide emulsion in a solutioxrof an organic compound having in its molecule a divalent radical corresponding to both the following tautomeric formulae 1 wherein It stands for a radical being a member of the group consisting of hydrogen, alkyl, aryl and acyl radlcles;

2. A process of developing an exposed silver halide emulsion in a solution of an aliphatic compound having in its molecule a divalent radical corresponding to both the following tautomeric formulae i I wherein stands for a radical being a member of the class consisting of hydrogen, allwl, aryl and acyl radicles; a

3. A process of developing an exposed silver halide emulsion in a solution of a heterocyclic compound having in its molecule a divalent radical corresponding to both the following tautomeric formulae -o-cn- -c o- 8 l'm. 1m in wherein R stands for a radical being a member of the-group consisting of hydrogen, alkyl, aryl and acyl radicles.

4. A process of developing an exposed silver halide emulsion in a solution of a-amino-acetoacetic acid ester.

5. A process of developing an exposed silver halide emulsion in a solution of l-p-chlorphenyl- 3-methyl-4-amino-pyrazolone-(5). I

JOHN EGGER'I'.

BRUNO 

